1. Field of the Invention
The present invention relates to a vehicle power unit including a speed reducing gear train including a starter driven gear relatively rotatably borne on a crankshaft rotatably borne on a crankcase constituting part of an engine body, a starting one-way clutch interposed between the starter driven gear and the crankshaft so as to permit power transmission from the starter driven gear to the crankshaft side, the speed reducing gear train and the starting one-way clutch being provided between a starter motor mounted to the engine body and the crankshaft with a transmission accommodated in the crankcase. The transmission includes gear trains for a plurality of gear speeds which can be selectively established, the gear trains being provided between a main shaft and a counter shaft which have axes parallel to the crankshaft.
2. Description of Background Art
A hybrid type motorcycle is known wherein an electric motor for exclusive use for imparting a torque to a power transmission system including a crankshaft of an engine mounted on the motorcycle is provided separately from a starter motor for imparting a starting torque to the crankshaft. See, for example, Japanese Patent Laid-Open No. 2007-269253.
In the motorcycle disclosed in Japanese Patent Laid-Open No. 2007-269253, however, the electric motor for exclusive use for imparting a torque to the power transmission system is needed, in addition to the starter motor. Therefore, the number of component parts is increased. In addition, the exclusive-use power transmission mechanisms have to be provided respectively for the starter motor and for the electric motor. This leads to a complicated structure and an enlarged power unit.